energy. laws of thermodynamics flow of energy in living things –oxidation & reduction free...
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Energy
• Laws of Thermodynamics• Flow of Energy in Living Things
– Oxidation & Reduction• Free Energy: Endergonic & Exergonic Rxs.• Activation Energy• Enzymes
– Forms– Activity
• ATP
Energy - Outline
Laws of Thermodynamics
First Law of ThermodynamicsEnergy cannot be created or destroyedEnergy can change form.
Second Law of ThermodynamicsDisorder (entropy) is increasing.Energy transformations proceed
spontaneously more ordered to a less ordered
less stable to more stable energy dissipates as heat.
Heat random motion of molecules.
Energy - the capacity to do workEnergy - the capacity to do work
Flow of Energy in Living Things
Potential Energy Kinetic Energy
Flow of Energy in Living Things
Oxidation - Reduction
Oxidation atom/molecule loses an electron.
Reduction atom or molecule gains an electron.
Redox reactions
- electron lost must be gained
Fig. 8.4 (TEArt)
Gain of electron reduction
Low energy
e–
A B
High energy
Loss of electron (oxidation)
A
o o
B
+ –
A* B*
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Oxidation - Reduction
Gain of energy reduction
Fig. 8.13 (TEArt)
N+
O CH2
H H
H
P O–O
OH OH
HH
O
CO
NH2
NMPreactivegroup
AMPgroup
O
P
O CH2
HH H
H
OH OH
O
O–O
HH
NH2
N N
NN
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Nicotinamide Adenine Dinucleotide Structure
8
NAD+ & NADHNAD = Coenzyme
= Electron Carrier Molecule
NAD+ oxidized low energy
NADH reduced high energy
Fig. 8.6a (TEArt)
Reactant
Product
Endergonic Reactions
Energymust besupplied.
Energy supplied
Energy released
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Fig. 8.6b (TEArt)
Reactant
Product
Exergonic Reactions
Energy released
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Energy released
Fig. 8.7 (TEArt)
Reactant
Product
Catalyzed
Uncatalyzed
Product
Reactant
Activationenergy
Energy supplied
Energy released
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Activation Energy
Fig. 8.8 (TEArt)
Active site Substrate
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Enzyme Structure and Function
Fig. 8.9 (TEArt)
Substrate = sucrose
1
Enzyme-substratecomplex
2
EnzymeStressesSubstrate
3
Productsreleased
4Bond
Enzyme
Active site
H2O
Glucose Fructose
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Enzyme Structure and Function
What do enzymes do?• Bring molecules together
• Orients molecules in correct position
• Strains (bends) molecules – Lowering of Activation Energy
• Releases products once formed
Factors Affecting Enzyme Activity
pH
Temperature
Fig. 8.11a (TEArt)
30
Human Enzyme Hotsprings prokaryote
Temperature of reaction (°C)
40 50 60 70 80
Ra
te o
f re
act
ion
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Temperature Effect on Enzyme Activity
Fig. 8.11b (TEArt)
Pepsin
pH of reaction
Trypsin
1 2 3 4 5 6 7 8 9
Rate of reaction
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pH Effect on Enzyme Activity
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
ATP
ADP+ P
Energy forendergonicreactions
Energy fromexergonicreactions
PhosphorylationStrongly
Endergonic
HydrolysisStrongly Exergonic
The ATP cycle
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
ATP
Chemical work Mechanical work Transport work
P
P
P
P
P
P
Molecule formed Protein moved Solute transported
Product
Reactants
Motorprotein
Membraneprotein Solute
+
How ATP powers cellular work
ADP + P
Fig. 9.2 (TEArt)
Triphosphate group
Sugar
Adenine
NH2
OP CH2
O
OP
O
OP
O
OH OH
ON
N
N
N
O-
O
O-O-
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ATP Structure
Energy Metabolism
How is ATP made?
1. ADP + Phosphate ATP
2. Mechanisms of ATP synthesis
Chemiosmosis
Substrate Level Phosphorylation
Fig. 9.3 (TEArt)
H+
ATP
ADP + Pi
Catalytichead
Intermembranespace
Mitochondrial matrix
Rod
Rotor
H+ H+
H+
H+ H+
H+H+H+
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ATP synthesis: Chemiosmosis
P
PEP
EnzymeADP
Adenosine
P
P
PATP
P
P
Adenosine
Pyruvate
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ATP Synthesis Substrate-Level Phosphorylation
END